This invention concerns a compressed-gas mechanical defoliator, designed to remove all or some of the leaves from plants, particularly vines.
Compressed-gas mechanical defoliators are already known that have many advantages compared to the processes and devices used before, namely manual, mechanical, chemical and thermal defoliators.
In particular, a compressed-gas mechanical defoliator is known and described in document FR 2.543.792 which has nozzles located at the end of pipes interlocked radially with a rotary distributor, so that said nozzles describe a circular trajectory. During one or more parts of this trajectory, the defoliator is able to blow on the vegetation, since said nozzles turn behind a cap that constitutes a deflector for the vegetation. The cap has one or more circular slots with the same radius corresponding to the trajectory of the nozzles, so as to limit their zones of action. It is also possible for the distributor to be adapted to supply air only when the nozzles describe a given angular sector.
This defoliator, although it has a higher yield than the others, has many disadvantages. Indeed, the pressure needed for defoliation is too great, which causes injuries to the fruit and seeds. This phenomenon is amplified by the high temperature of the air blown, which can reach 130xc2x0 C.
The yield of this defoliator is also insufficient. Indeed, since rotation of the nozzles is combined with displacement of the drive vehicle that carries it, said nozzles pass over the same place on the vegetation only once or not many times, which often makes it necessary to make a second pass or be satisfied with limited defoliation.
A compressed-gas rotary distributor with different jets is also known for agricultural machines to defoliate trees and bushes, as described in patent FR 2.712.461. This distributor has different curved pipes, equipped with a nozzle that blows air around through circular holes made in a case toward the trees or plants, so as to eliminate only the leaves in front of the fruit-bearing zone by lifting them up.
On this device, special orientations are given the nozzles during construction, by appropriately bending the pipes upstream from said nozzles; however, these orientations, defined a priori, do not always make it possible to obtain a satisfactory yield.
Generally speaking, a defoliator is installed on a drive vehicle, with or without a tractor, whose force drives an air compressor; its disadvantage is a sometimes large variation in air pressure, which is a function of the power of the drive and/or tractor and the contour of the ground, given that the compressor is not driven at constant speed. Now, for effective defoliation, it is preferable to have control of the air pressure.
The goal of this invention is to fix these disadvantages. This invention, as it is characterized, solves the problem, which consists of creating a compressed-gas mechanical defoliator with which, on one hand, the air pressure can be controlled all during defoliation, whatever the conditions under which it is done and, on the other hand, the leaves to be eliminated are stressed effectively enough to obtain maximum elimination of the leaves in a single pass.
The type of compressed-gas mechanical defoliator in the invention, which has at least one nozzle mounted on the end of a pipe interlocked radially with a compressed gas rotary distributor turning behind a vegetation deflector, is mainly characterized by the fact that it has several nozzles distributed over different concentric circles, by the fact that the vegetation deflector has means of allowing controlled passage of the compressed gas jets and by the fact that it is equipped with means of regulating the gas pressure in relation to an adjustable set point during defoliation from the operator""s post of the vehicle carrying it.
Preferably, the distance between nozzles in relation to the Y axis of rotation of the compressed gas distributor, their inclination and orientation are adjustable.
In one embodiment, the means for controlled passage of the compressed gas jets through the vegetation deflector is composed of circular slots, with a radius corresponding to that of the circular trajectories described by the nozzles. These circular slots can be made in a mask that can be detached, making it possible to change the characteristics of the slots by simple permutation to adapt them to different defoliation situations.
In a second embodiment, the means of controlled passage for the compressed gas jets is composed of a perforated disk, interlocked in rotation with the nozzles, mounted in a circular opening with a corresponding diameter made in the wall of the deflector coaxial to the Y axis of the distributor.
In a third embodiment, the means of controlled passage of the compressed gas jets is composed of a grid.
In a process designed mainly for defoliating vines, this is done simultaneously by two defoliation heads located one behind the other with a certain vertical offset Z.
The nozzles can be inclined in relation to the Y axis of rotation of the distributor, at an angle between 0 and 45xc2x0, preferably 15xc2x0.
The device, which allows the distance and/or inclination of the nozzles to be regulated in relation to the Y axis of rotation of the distributor, is comprised of sleeves with a clamping chuck attached radially to the distributor, in which the feed pipes for the compressed gas nozzles are slide-mounted, and semicircular rings with multiple adjustment orifices, attached perpendicular to the pipes. An indexing rod parallel to each sleeve and interlocked with it freely penetrates a particular orifice. The adjustment orifices are distributed over a radius corresponding to the one described by the indexing rod and their angular deviation is 5xc2x0.
The device that allows the orientation of the nozzles to be adjusted is comprised of a ring with peripheral notches attached perpendicular to the base of the nozzles, in relation to which their tip forms, by construction, a predetermined angle. The base of the nozzles is encased in the curved end of the pipes which have, at their outlet, a circular adjustment flange for orienting the tip of the nozzle and attaching it by means of at least one screw that goes into one of the notches on the adjustment ring, after the nozzle is oriented in the chosen direction.
The advantages derived from this invention consist basically of the fact that all the parameters involved in the quality of the defoliation. This consequently makes it possible to adapt it to special conditions associated with the nature of the vegetation, its level of development and meteorological conditions. These parameters are adjustable, for the most part, on site, with the possibility of modulating the pressure of the compressed gas during defoliation, to take into account certain changes in the initial conditions determined, such a the arrival of rain, for example.